Two-pipe disc refiner



V. W. CANClLLA TWO April 15, 1969 -PIPE DISC REFINER Filed Aug. l5. 1966 United States Patent O U.S. Cl. 241--146 7 Claims ABSTRACT F THE DISCLOSURE A four-disc refiner wherein the hydraulic pressures on both sides of the rotating disc are balanced so that the disc maintains a centered position between the stationary discs.

The present invention relates to improvements in refiners and more particularly to a refiner of the type which is used for refining paper pulp stock and particularly to a four-disc refiner.

In a four-disc stock refiner a rotating disc carries refining plates on its surfaces which face stationary refining discs. Stock is fed to the refiner at the center of the disc and flows outwardly between the stationary discs and the rotating disc. The working faces of the rotating disc `are subjected to hydraulic forces of the stock fiowing through the refining zones between the stationary and rotating discs. To maintain the rotor in a center position relative to the stationary discs it is necessary, unless an extrinsic large balancing force is applied, to have the hydraulic forces on both sides of the rotating disc the same. It is conventional in many refiners to drive the disc with a shaft which projects from one face of the disc so that the exposed surface area of the disc face from which the shaft projects is smaller in area than the other face. This causes an imbalance in forces.

It is accordingly an object of the present invention to provide a four disc refiner wherein the hydraulic pressures on both sides of the rotating disc are `balanced so that the disc maintains a centered position between the stationary discs.

A still further object of the invention is to provide a unique way of having a lower pressure on the outer face of the disc of a refiner than on the side having the driving shaft.

A still further object of the invention is to provide an improved four-disc refiner having a simplified piping arrangement wherein only one supply pipe may be used for the slurry inlet and one pipe used for the slurry outlet.

A still further object of the invention is to provide a four-disc refiner wherein the rotating discs can be serviced and inspected or changed without disconnecting pipes or fiow connections.

A feature of the present invention is the provision of a four-disc refiner with a refining rotating disc having inner and outer faces with annular refining surfaces thereon, a supporting shaft carrying the rotor disc at its end and projecting from the inner face of the disc, stationary relining surfaces in a housing facing the inner and outer surfaces of the rotor and defining first and second refining zones respectively with inner and outer rotor surfaces, a stock flow inlet passage leading to the first refining space along the shaft, and a second stock fiow passage preferably leading from the inlet passage through the rotor to the second refining space with the stock encountering a pressure drop through said passage so that lesser unit hydraulic pressure is felt on the outer face of the rotor disc and the overall axial forces on the disc are balanced.

Other objects, advantages and features will become more apparent with the teaching of the principles of the present invention in connection with the disclosure of the 3,438,586 Patented Apr. 15, 1969 ICC preferred embodiment thereof in the specification, claims and drawings, in which:

FIGURE 1 is a schematic view shown in section of a refiner embodying the principles of the present invention; and

FIGURE 2 is a detailed plan view of a rotor shown as it would appear along line II-II of FIGURE 1 with the shaft and other portions removed.

0n the drawing FIGURE 1 shows a refiner with a rotor disc 10. The disc is relatively fiat and circular in shape as illustrated in FIGURE 2 and is provided with an inner face 10a and an outer face 10b. On the inner face are annular refining surfaces 11 usually in the form of refining cutters or blades attached to the disc in a Amanner which will be appreciated by those versed in the art and need not be described in detail. On the outer face 10b is an annular refining surface 12. Facing the refining surfaces 11 and 12 are stationary refining surfaces 13 and 14. These stationary annular surfaces are mounted in the inner chamber 22 of a housing 21 enclosing the refiner.

The space between the rotary refining surface 11 and the stationary refining `surface 13 forms a first refining zone 15. The space between the refining surface 12 and the stationary refining surface 14 forms a second refining zone 16. In other words the inner refining surface 11 faces the first refining zone 15 and the outer refining surface 12 faces the second refining zone 16.

The rotor is carried and driven by a shaft 17 fioatingly supported in the housing and suitably carried on bearings and driven. The mounting of the shaft will be fully understood -by those versed and need not be described in detail. The shaft projects from the inner face 10a of the rotor and is suitably secured thereto with the shaft shown as admitted from the disc 10 in FIGURE 2.

Stock is fed to the refiner along the shaft 10 through an inlet passage 18. The inlet passage is shown as extending annularly coaxially around the shaft 17 to supply stock 4uniformly to the first refining Zone 15.

To supply stock to the second refining zone 16 a stock fiow passage is provided preferably in the form of flow ports 20 through the rotor. The rotor is thus preferably made in spoked form and the stock flow passages have a predetermined size relationship to the inlet passage 18 in order to cause a predetermined pressure drop.

As will be observed, the outer face 10b of the rotor has an overall larger exposed -area than the inner face 10a inasmuch as the shaft 17 covers a portion of the exposed area. Thus the hydraulic pressure of the stock will act on a smaller area on the face 10a than on the face 10b.

To compensate for this difference in area the pressure of the stock on the face 10b is controlled to be of a reduced pressure. This control is obtained by predetermining the size of the rotor inlet passages 20 so that predetermined pressure drop is obtained and the overall hydraulic force on the face 10b will be balanced or substantially the same as the overall hydraulic force on the face 10a.

While different stock slurries have different flow characteristics and the degree of resistance to flow varies in the stock fiow passing through the openings 20- in the rotor, rotor openings have been discovered which will effect a proper pressure drop with different types of stock and different pressures. In a preferred form the openings 20 have a size elationship to the inlet 18 so that a pressure drop of 0.4 to 0.6 p.s.i. occurs for every 10 p.s.i. of stock inlet pressure in the passage 18.

The preferred range of pressure drop across the rotor (enclosed with the openings 20) is in the range of .O4 to .06 ti-mes the inlet pressure.

The following provides an example of a range of sizes which have been accomplished using the principles of the present invention with refiners a size from 12 inches to 54 inches:

inner face of the rotor disc to supply stock to the first refining space,

Rotor Percent of Refiner size, Size inlet Area inlet Area rotor openings reqd area Area rotor Shaft AP factor inches pipe pipe openings area reqd, in rotor 50% inlet openings The following indicates the relationship between rotor area and disc area on the inner surface 10a of the disc with an example being given for a ZO-inch rener.

Rotor areazdisc area-rotor opening Rotor diameter=343/s"area=925 sq. in. Shaft diameter=7%-area=47 sq, in. Z-pipe Duo Flo open area in hub=45 sq. in. Effective rotor area=rot0r area-open area E.R.A.=925*45.=880 sq. in.

To balance hydraulic forces on both sides of rotor the difference in pressures must bez' X inlet p.s.i.

shaft area AP una.

Xinlet pressure:

Assume inlet 30 p.s.i.

AP=.054 30=1.6 p.s.i. pressure drop requested Thus it will be seen that I have provided an improved disc refiner which meets the objectives and advantages above set forth and which accomplishes automatic hydraulic balanced forces on the rotor. The housing can have a single inlet and single outlet pipe and servicing and inspection of the rotor can occur Without disconnection of lines.

I claim as my invention:

1. A refining mechanism comprising in combination,

a refining rotor disc having inner and outer faces with annular refining surfaces thereon,

a supporting shaft carrying the rotor disc at its end and pojecting from the inner face of the disc,

stationary refining surfaces facing the inner and outer surfaces of the rotor and defining first and second refining zones respectively with the inner and outer rotor surfaces,

a stock owinlet passage leading along the shaft to the Xinlet p.s.i.=.053 inlet p.s.i.

a stock flow passage means leading from the inlet passage to the outer face of the rotor disc to supply stock to the second refining space,

the area of the inner face of the rotor disc exposed to Stock being smaller than the area of the outer face,

said passage means being of a size so that the total pressure drop of stock fiowing through said passage means is equal to the difference between the axial force of the stock on the inner face of the disc and the force of the stock on the outer face of the disc.

2. A refining mechanism in accordance with claim 1 wherein said passage means comprises a flow passage means through the rotor disc.

3. A refining mechanism in accordance with claim 1 wherein said passage means comprises a plurality of uniformly spaced and uniformly sized openings positioned uniformly relative to the rotor axis.

4. A refining mechanism in accordance with claim 1 wherein the passage means in sized relative to the stock fiow inlet to afford a pressure drop in the range of .04 to .06 times the inlet pressure in said inlet passage.

S. A refining mechanism in accordance with claim 1 wherein the area of said passage means relative to said inlet passage is such that there is a pressure drop of .5 p.s.i. for every 10 p.s.i. of stock inlet pressure in said flow inlet passage.

6. A refining mechanism in accordance with claim 1 including a -housing supporting said stationary refining surfaces with an outlet passage leading from said refining zone at the outer periphery of said disc.

7. A refining mechanism in accordance with claim 6 wherein said inlet stock flow passage and said outlet passage are the only passages leading to and from said housing.

References Cited UNITED STATES PATENTS 2,204,057 6/ 1940 Swartz 241-296 2,991,020 7/1961 Jones 241-146 3,371,873 3/1968 Thomas 241-146 GERALD A. DOST, Primary Examiner.

U.S. Cl. X.R.

Dedication 3,438,586.Vz'fncent W. Canalla, Pittsfield, Mass. 'FWO-PIPE DISC RE- FINER. Patent dated Apr. 15, 1969. Dedication led May 6, 1977, by the assignee, Beloit Corporation. Hereby dedicates to the Public the entire term of said patent.

[Oficial Gazette August 23, 1977.] 

